Deflection coil

ABSTRACT

Deflection coil, obtained by bending into a part-cylindrical shape a coil comprising a plurality of glue-coated insulated wires simultaneously wound side by side without insulating intermediate layers, each wire forming a flat spiral.

United States Patent 11 1 Pax et al.

1451 Jan. 9, 1973' 541' DEFLECTION COIL' 3,412,354 11/1968 Sattler ..336/205 3,423,706' 1 1969 S t I. 335 213 lnventorsi Wilhelmus Petlfus Johannes Fran- 2 949 593 33 ciscus Pax; Henricus Johannes an 3,488,541 1/1970 Barbin 335/213 Rooy, bbth 0f Emmasingel, Eind- 3,396,356 8/1968 Whipplem" 336/206 hoven, Netherlands 3,007,087 10/1961 COrpew 335/213 3,088,200 5/l963 Birdsall et a1... ....219/i49 ASSIgHeeI Phillps o p" New York, 3,234,632 2/1966 Marley ..336/200 [22] 1 Filed: 1970 Primary Examiner-George Harris [2]] Appl. No.: 89,785 Att0rneyFrank R. Trifari 57 T [30] Foreign Application Priority Data 1 ABS RACT Deflection-coil, obtained by bending into a part-cylin- Dec.4, 1969 Netherlands ..69i8204 drica] shape a il comprising a lurality of glue- 1 7 1 coated insulated wires simultaneously wound side by U.S. side without insulating intermediate layers each wire [51] :InL Cl .1101! 5/00 forming a flat spiral. [58] Field of Search .,....3'36/186, 206, 205'; 335/213,

' I 3 Claims, 3 Drawing Figures [56] References Cited UNITED STATES PATENTS 2,167,379 I 7/1939 Tolson, ..'.....3l3/76 PATENTED JAN 9 I975 H 2% F g f v o F E s E Q IN Vlz'N'l'ORS WILHELMUS RJ.F. PAX HENRICUS J. VAN ROOY AGENT DEFLECTION COIL This invention relates to a deflection coil, more particularly, to a flat coil bent over, subsequent to winding, at least partly into the form of a cylindrical plane for producing a magnetic deflection field in a cathode-ray tube, around the tubular envelope of which usually two coils of said kind for the horizontal deflection and two coils for the vertical deflection are arranged in pairs diametrically opposite each other. By winding the coil in a flat shape and by subsequently bending it into the cylindrical shape the winding operation is simplified.

Deflection coils foruse on color television camera tubes in which a separate cathode-ray tube is used for each of the three fundamental colors, have to satisfy stringent requirements as to identity of the coils to be employed in one and the same apparatus, for example, for horizontal deflection, in order to avoid imaging defects. It is known to form a flat deflection coil from a plurality of relatively fitting rectangular coil portions of progressing size and to bend the set of coils, baked together to a slightly rigid unit, into the required semicylindrical shape. Without prohibitively high costs it has hitherto not been possible to wind the coil portions of normal wire with such complete regularity that subsequent bending of the coil does not disturb this regularity so that in this way the three accurately identical coil pairs cannot be obtained.

An object of the invention is to provide a structure which does permit of doing so.

The coil in accordance with the invention is characterized in that the coil to be bent comprises a plurality of glue-coated, insulated wires simultaneously wound side by side without intermediate insulating layers, the turns of each wire each forming a flat spiral. The spirals are connected outside the coil in known manner either in series, in parallel or in series-parallel. Winding is completely regular since it does not comprise crossing winding portions and by using wire of uniform thickness accurately identical coils can be obtained at a low cost. It also has been found that the regularity of the coils will not be disturbed by subsequent bending thereof.

It should be noted that the bifilar winding of saddleshaped and toroidal deflection coils is known. However, the coils concerned there assume the fairly complicated, final shape during the winding operation itself so that they are not first wound in a simple flat form. The regularity of winding of these coils cannot be improved by multifilar winding and the purposes aimed at are quite different.

There is furthermore known a coil for other purposes than deflection which is wound from an insulating strip having a plurality of parallel printed conductors. The width of the strip is comparatively large and this structure is intended for use in coils having a comparatively large axial size, which coils need not be bent after windmg.

The invention will be described more fully with reference to the accompanying drawing, in which:

FIG. 1 illustrates the winding of a deflection'coil in accordance with the invention,

FIG. 2 is a side elevation of such a coil, and

FIG. 3 shows the final shape of the coil.

FIG. 1 shows somewhat simplified the winding of a flat, rectangular coil (see also FIG. 2) comprising a number, in this case four, of insulated wires I wound side by side without insulating intermediate layers. The

wires, provided with a preferably thermoplastic glue layer which is solid at room temperature, are wound from four supply reels 3 (one of them is shown in FIG. 1) in a jig formed by a rectangular winding mandril 5 and two detachable flanges 7. The distance between the flanges (for example, about 2 mms) is equal to four times the wire thickness inclusive of insulation and glue layer. The four wires (shown in a sectional view in FIG. 1 in the winding jig) coil up to form four flat spirals, which, provided the wire thickness is constant, are completely regular even with a fairly large number of layers. Furthermore, there is no need to take special precautions because the wires do not cross each other at any place and the position of each turn is determined by the winding jig and the adjacent windings. It is preferred to wind one or more portions, in this case the second half of the coil,about four auxiliary pins 9 passed through the winding jig, shown in in FIG. 2. The coil then more nearly approaches the rectangular shape which provides an optimum magnetic field.

After baking the coil into a single unit, which may be performed in a conventional manner by passing a current pulse through each of the four spirals in the winding jig, the coil can be bent in a second jig into the desired cylindrical shape (see FIG. 3) for matching a camera tube 11. The four spirals may be connected in series or in parallel, or they may be electrically interconnected in a different way.

The secondary deformations involved in bending the coil into the cylindrical shape, for example, by relative shift of the spirals appear to remain within the tolerances of accuracy acceptable for the purpose concerned in the form of winding described with the small coil thickness required for the kind of deflection coils concerned.

What is claimed is:

l. A CRT deflection coil having a partially cylindrical shape comprising, a plurality of glue-coated insulated wires that are located side by side without an intermediate insulating layer therebetween so that each wire forms a flat spiral winding with an aperture and a plurality of turns, each of said apertures being substantially identical, said windings being mounted together with the apertures in alignment to form an integral deflection coil unit having a plurality of identical concentric flat spirals disposed side by side, and wherein the flat coil composed of the flat spiral windings has the shape of a partial cylinder.

2. A deflection coil as claimed in claim 1 wherein each of the wires that make up a spiral windinghave a cylindrical cross-section, said wires being adapted to be connected together in a plurality of configurations.

3. A deflection coil as claimed in claim 1 wherein each of the wires that make up a spiral winding have a substantially identical cylindrical cross-section. 

1. A CRT deflection coil having a partially cylindrical shape comprising, a plurality of glue-coated insulated wires that are located side by side without an intermediate insulating layer therebetween so that each wire forms a flat spiral winding with an aperture and a plurality of turns, each of said apertures being substantially identical, said windings being mounted together with the apertures in alignment to form an integral deflection coil unit having a plurality of identical concentric flat spirals disposed side by side, and wherein the flat coil composed of the flat spiral windings has the shape of a partial cylinder.
 2. A deflection coil as claimed in claim 1 wherein each of the wires that make up a spiral winding have a cylindrical cross-section, said wires being adapted to be connected together in a plurality of configurations.
 3. A deflection coil as claimed in claim 1 wherein each of the wires that make up a spiral winding have a substantially identical cylindrical cross-section. 